package ej.i2;

import java.util.HashMap;
import java.util.Map;

public class MapKeySetTest {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		Map map = new HashMap();
		map.put("1", 1);
		map.put("2", 2);
		map.put("3", 3);
		System.out.println(map.keySet());
		System.out.println(map.keySet());
		map.put("4", 4);
		System.out.println(map.keySet());

	}

}
